This is in the footnote 12: "Of course, if TikTok is removed, many children will just move to TikTok’s competitors: Instagram Reels and YouTube Shorts. This is why it’s so important for countries to follow Australia’s lead: raise the age for opening social media accounts to 16 and require the companies to enforce it."
But indeed focusing on TikTok is probably counterproductive for establishing general regulation. Why not just apply the same regulation to TikTok?